This paper describes a new class of flight control actuators using Post-Buckled Precompressed (PBP)
piezoelectric elements to provide much improved actuator performance. These PBP actuator elements are modeled
using basic large deflection Euler-beam estimations accounting for laminated plate effects. The deflection
estimations are then coupled to a high rotation kinematic model which translates PBP beam bending to stabilator
deflections. A test article using PZT-5H piezoceramic sheets built into an active bender element was fitted with an
elastic band which induced much improved deflection levels. Statically the bender element was capable of
producing unloaded end rotations on the order of ±2.6°. With axial compression, the end deflections were shown to
increase nearly 4-fold. The PBP element was then fitted with a graphite-epoxy aeroshell which was designed to
pitch around a tubular stainless steel main spar. Quasi-static bench testing showed excellent correlation between
theory and experiment through ±25° of pitch deflection. Finally, wind tunnel testing was conducted at airspeeds up
to 120kts (62m/s, 202ft/s). Testing showed that deflections up through ±20° could be maintained at even the highest
flight speed. The stabilator showed no flutter or divergence tendencies at all flight speeds. At higher deflection
levels, it was shown that a slight degradation deflection was induced by nose-down pitching moments generated by
separated flow conditions induced by extremely high angles of attack.
This paper discusses modeling, simulations and experimental aspects of active aeroelastic control on aircraft wings by
using Synthetic Jet Actuators (SJAs). SJAs, a particular class of zero-net mass-flux actuators, have shown very
promising results in numerous aeronautical applications, such as boundary layer control and delay of flow separation. A
less recognized effect resulting from the SJAs is a momentum exchange that occurs with the flow, leading to a
rearrangement of the streamlines around the airfoil modifying the aerodynamic loads. Discussions pertinent to the use of
SJAs for flow and aeroelastic control and how these devices can be exploited for flutter suppression and for aerodynamic
performances improvement are presented and conclusions are outlined.
Aircraft are often confronted with distinct circumstances during different parts of their mission. Ideally the
aircraft should fly optimally in terms of aerodynamic performance and other criteria in each one of these mission
requirements. This requires in principle as many different aircraft configurations as there are flight conditions, so
therefore a morphing aircraft would be the ideal solution. A morphing aircraft is a flying vehicle that i) changes
its state substantially, ii) provides superior system capability and iii) uses a design that integrates innovative
technologies. It is important for such aircraft that the gains due to the adaptability to the flight condition are not
nullified by the energy consumption to carry out the morphing manoeuvre. Therefore an aeroelastic numerical
tool that takes into account the morphing energy is needed to analyse the net gain of the morphing. The code
couples three-dimensional beam finite elements model in a co-rotational framework to a lifting-line aerodynamic
code. The morphing energy is calculated by summing actuation moments, applied at the beam nodes, multiplied
by the required angular rotations of the beam elements. The code is validated with NASTRAN Aeroelasticity
Module and found to be in agreement. Finally the applicability of the code is tested for a sweep morphing
manoeuvre and it has been demonstrated that sweep morphing can improve the aerodynamic performance of an
aircraft and that the inclusion of aeroelastic effects is important.
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